1. Field of the Invention
This invention relates to a knee protection airbag apparatus having an airbag which is accommodated by being folded at a lower portion in front of the knees of a passenger seated on a seat, and expands and inflates upward in a rear direction of a vehicle in such a fashion as to be capable of protecting the knees of the passenger when an inflating gas is let in the airbag.
2. Description of the Related Art
A knee protection airbag apparatus having a construction described in JP-A-2003-205816 is known. The knee protection airbag apparatus of the prior art is arranged below a steering column in front of a driver's seat and tethers are arranged in a transverse direction inside the airbag after inflation is complete. The tethers are arranged so as to increase the thickness of the portion which impedes motion of the knees of the passenger and to decrease the thickness of the portion by the steering column.
When motion of the knees of the passenger is impeded by the airbag inflated by the knee protection airbag apparatus having the construction described above, motion of the shins of the passenger also often is impeded by the airbag in addition to the knees of the passenger. When the airbag expands and inflates while the passenger is close to a body side portion of the vehicle, the airbag inflating with the inflating gas is likely to push unnecessarily the shins of the passenger because the gap between the shins and the body side portion is small.